Custom block tags
Block tags are tags of the form: {func} .. {/func}. In other
words, they enclose a template block and operate on the contents of this
block. 
Block functions take precedence over normal tags of the same name, that is, you
cannot have both custom tag {func} and block tag {func}..{/func}.
- 
By default, your function implementation is called twice by Smarty: once for the opening tag, and once for the closing tag. (See $repeatbelow on how to change this.)
- 
Only the opening tag of the block has attributes. All attributes are contained in the $paramsvariable as an associative array. The opening tag attributes are also accessible to your function when processing the closing tag.
- 
The value of the $contentvariable depends on whether your function is called for the opening or closing tag. In case of the opening tag, it will be NULL, and in case of the closing tag it will be the contents of the template block. Note that the template block will have already been processed by Smarty, so all you will receive is the template output, not the template source.
- 
The parameter $repeatis passed by reference to the function implementation and provides a possibility for it to control how many times the block is displayed. By default$repeatis TRUE at the first call of the block function (the opening tag) and FALSE on all subsequent calls to the block function (the block's closing tag). Each time the function implementation returns with$repeatbeing TRUE, the contents between{func}...{/func}are evaluated and the function implementation is called again with the new block contents in the parameter$content.
Example:
<?php
function smarty_block_translate($params, $content, \Smarty\Template $template, &$repeat) {
    // only output on the closing tag
    if (!$repeat){
        if (isset($content)) {
            $lang = $params['lang'];
            // do some intelligent translation thing here with $content
            return $translation;
        }
    }
}
$smarty->registerPlugin(Smarty\Smarty::PLUGIN_BLOCK, 'translate', 'smarty_block_translate');
This can now be used in your templates as follows: